The present invention generally pertains to the field of power supplies, and more particularly concerns a power system that supplies power to a system backplane having a split power plane.
In telecommunications (telco) environments, it is important that the various switching systems used to transfer calls and data across communication networks be provided with a constant power supply, regardless of external conditions, such as power failures. As a result, many telecommunications (telco) environments provide battery power sources rather than AC power sources, although AC power sources may be used to provide a DC supply to the telco equipment with a battery backup for emergency situations.
Because many telco companies have been in operations for decades, the power provided at various power distribution panels within their facilities were often designed and built many years ago, when much of the telco switching equipment required less power. For example, many telco environments provide a maximum of 60 A of current at their power distribution panels. As a result, the maximum power that can delivered to a switching device from the existing distribution panels is limited.
As an option, new switching equipment could be wired directly to a battery source and be physically located close to the battery source to meet the Bellcore power distribution requirements of the equipment. However, this leads to a very expensive and time-consuming installation, as it requires significant changes to the telco facility.
A system and method are described for supplying power to electronic systems, such as telco switching systems, in a manner that enables approximately twice as much power to be supplied to the electronic system than would normally be available using conventional power supply systems and methods. The power supply system includes a system backplane having a split power plane, wherein each half of the split power plane receives power from a separate power supply circuit. Preferably, the power supply circuits comprise circuit portions of a common power entry module (PEM), which typically will receive input power from a pair of service points provided by a DC such as a battery source or an AC/DC power conversion source. The PEM and system backplane include circuitry to enable a single backplane to be powered by two separate power supplies, thereby providing the system backplane and any connected logic cards with approximately twice as much power than could normally be provided by a single service point. To facilitate this capability, the PEM includes circuitry for detecting the power supplied by each of its power supply circuits and for automatically shutting down power supply to the system backplane in the event of a detected failure condition, such as an undervoltage condition on one or both of the power supplies, and a voltage differential between the power supplies that exceeds a predetermined threshold.
The system and method also provides for the use of a second PEM that is used in situations requiring a redundant power supply system. In this configurations, two power supply circuits, one from each PEM, are used to supply power to each half of the system backplane, thereby forming two sets of power supply circuits. This is facilitated, in part, by connecting each set of power supply circuits together in a diode ORed manner, whereby adequate power will be provided to a given half of the system backplane as long as at least one of the power supply circuits in particular set is operating normally.
Other features and advantages of the present invention will be apparent from the accompanying drawings and from the detailed description that follows below.